Clinical experience with the zero-pressure-fixed Medtronic Intact bioprosthetic valve

The Medtronic Intact porcine valve bioprosthesis was inserted in 219 patients between 1983 and 1990. Mean patient age was 52 years and mean follow up 33.3 months. There was only one example of structural valve degeneration at 25 months, giving an actuarial freedom of 99% at 6 years. Reoperation was performed in 7 patients. Freedom from reoperation was 93% at 6 years, from infective endocarditis 96%, from thrombo-embolism 91% and from valve-related complications 86%. Doppler echocardiography revealed non-significant incompetence in 8 instances and mild leaflet thickening of 5 valves. Valve gradients and areas were unchanged between two Doppler studies 2 years apart of valves in the mitral position, and were reduced in valves in the aortic position from 17 +/- 5.2 mmHg to 13 +/- 2.8 mmHg (P = 0.02). These medium-term results are considered very encouraging. The theoretical considerations underlying the use of zero-pressure glutaraldehyde fixation, which is the technique used for the Intact valve, are detailed elsewhere in this issue [1]. The Intact valve is treated with toluidine blue as a calcium-retarding agent and is mounted on a Dacron-covered acetyl copolymer (Celcon) stent with flexible posts. The normal profile of the porcine aortic valve is maintained.